A serial killer is typically defined as an individual who has killed three or more people over a period of more than a month, with down time (a "cooling off period") between the murders, and whose motivation for killing is usually based on psychological gratification. Some sources disregard the "three or more" criteria, and define the term as "a series of two or more murders, committed as separate events, usually, but not always, by one offender acting alone" or, including the vital characteristics, a minimum of two murders. Often, a sexual element is involved in the killings, but the FBI states that motives for serial murder include "anger, thrill, financial gain, and attention seeking". The murders may have been attempted or completed in a similar fashion and the victims may have had something in common, for example, occupation, race, appearance, sex, or age group.

Serial killers are not the same as mass murderers, nor are they spree killers, who commit murders in two or more locations with virtually no break in between.

Edmund Emil "Big Ed" Kemper III (born December 18, 1948), also known as "The Co-ed Killer", is an American serial killer and necrophile who was active in California in the early 1970s. He started his criminal life by murdering his grandparents when he was 15 years old. Kemper later killed and dismembered six female hitchhikers in the Santa Cruz area. He then murdered his mother and one of her friends before turning himself in to the authorities days later. Kemper is noted for his imposing physicality, standing 6'9" (2.06 m) and weighing over 300 pounds (140 kg).

Kemper was the middle child and only son born to Edmund Emil Kemper, Jr. (1919–1985) and Clarnell E. Strandberg (1921–1973). As a child he was extremely bright, but displayed sociopathic behavior from a young age, including cruelty to animals; he purportedly fatally stabbed a pet cat at age 13. He acted out bizarre sexual rituals with his sisters' dolls and exhibited a dark fantasy life. He recalled later that his eldest sister pushed him into the deep end of a swimming pool and he had to struggle to get out and nearly drowned. She also pushed him within yards of a moving train.

Christopher Bernard Wilder (13 March 1945 – 13 April 1984) was a serial killer who abducted and raped at least ten women and killed at least eight of them during a spree across the United States in early 1984. His rampage began in Florida and continued across the country through Texas, Oklahoma, Nevada, California and New York before he committed suicide during a struggle with police in New Hampshire on April 13.

He is also believed to have raped girls aged 10 and 12 in Florida during 1983. For many years since his death, Wilder has also been considered the prime suspect in the unsolved Wanda Beach murder of two teenage girls in Sydney, Australia in 1965.

Wilder was born in Australia. His father was an American naval officer and his mother an Australian. He almost died at birth, but recovered, only to almost drown in a swimming pool at age two. In 1962 or 1963, he pleaded guilty in the case of a gang-rape at a beach in Sydney and was put on probation, during which time he also received electroshock therapy. There is some evidence to suggest that this course of treatment only exacerbated his violent sexual tendencies. It is known that he had virtually memorized the text of the 1963 novel The Collector by John Fowles, in which a man keeps a woman in his basement against her will until she dies. A copy of the novel was found among his possessions after his death.

Rex Elvie Allen (December 31, 1920 – December 17, 1999) was an American film actor, singer and songwriter, known as the Arizona Cowboy, particularly known as the narrator in many Disney nature and Western film productions. For contributions to the recording industry, Allen was honored with a star on the Hollywood Walk of Fame.

Allen was born to Horace E. Allen and Luella Faye Clark on a ranch in Mud Springs Canyon, 40 miles from Willcox, Arizona. As a boy he played guitar and sang at local functions with his fiddle-playing father until high school graduation when he toured the Southwest as a rodeo rider. He got his start in show business on the East Coast as a vaudeville singer, then found work in Chicago as a performer on the WLS-AM program, National Barn Dance. He left the show in 1949 and moved to Hollywood. In 1948 he signed with Mercury Records where he recorded a number of successful country music albums until 1952, when he switched to the Decca label where he continued to make records into the 1970s. He also recorded one album for Buena Vista (Disney, pictured) in the 1960s, although sources vary on the date of issue.

Jerome Henry "Jerry" Brudos (January 31, 1939 – March 28, 2006) was an American serial killer and necrophiliac, also known as "The Lust Killer" and "The Shoe Fetish Slayer".

Brudos was born in Webster, South Dakota, and was the youngest of four sons. His mother had wanted a girl and would dress Brudos in girl's clothing. She would also constantly belittle him and treat him with disdain, as well as abuse him. As a child, Brudos and his family would move into different homes in the Pacific Northwest, before settling in Salem, Oregon.

He had a fetish for women's shoes from the age of five, after playing with spike-heeled shoes at a local junkyard. He also reportedly attempted to steal the shoes of his first grade teacher. He also had a fetish for women's underwear, and had claimed that he would steal underwear from female neighbors as a child. He spent his teen years in and out of psychotherapy and mental hospitals. He began to stalk local women as a teenager, knocking down or choking them unconscious, and fleeing with their shoes.